Accuracy of fetal sex determination by ultrasound.

The accuracy of fetal sex determination was tested in 101 consecutive pregnancies routinely examined by ultrasound in the 32nd gestational week. Sex determination was done when penis/scrotum or vulva could be discerned between the thighs of the fetus. Fetal sex could be determined in 75 per cent of the male infants and in 73 per cent of the females. The wrong sex was determined in 3 per cent of all examinations. In 25 and 21 per cent of female and male fetuses respectively sex determination could not be accomplished. The results were better in the 32nd than in the 38th week. The significance of fetal sex determinations is discussed.